1. Field of the Invention
The present invention relates to a communication system, a communication apparatus, and a control method thereof.
2. Description of the Related Art
USB (Universal Serial Bus) is a conventional technology developed as a means to connect peripheral devices to a personal computer. The personal computer generally acts as the host, whereas the peripheral device, exemplified by a printer, image scanner, or the like, acts as the device.
However, in recent years, the USB standard is also being used for connecting other consumer devices to one another, and thus devices aside from personal computers are beginning to function as USB hosts as well. An example of this is a direct printing scheme, whereby a digital still camera (DSC) and a printer are connected 1-to-1 via USB, and photographic images stored in the digital still camera are printed out via the printer. In such a case, the printer functions as the host, and the digital still camera functions as the device.
Generally speaking, printers including such direct printing functionality have both a USB device port, used when functioning as a device and connecting to a personal computer, and a USB host port, used when functioning as a host and connecting to a digital still camera.
Furthermore, in recent years, the wireless USB (WUSB) protocol, which makes wireless USB communication possible, has been standardized, and thus communication that once was implemented through wired USB can now be implemented wirelessly.
Using the WUSB system makes it possible to realize wireless direct printing.
WUSB functionality can be integrated directly into the host or the device, and can also be implemented by connecting a WUSB adapter to a device already equipped with a standard USB interface.
Furthermore, printers can be provided with wireless-direct-printing functionality and WUSB adapter functionality as well.
In the following descriptions, a printer provided with both WUSB adapter functionality and wireless-direct-printing functionality should be called a “multiple control station”.
As an example of related art, a technique for connecting a plurality of wireless terminals to a single USB device has been disclosed (Patent Document 1: Japanese Patent Laid-Open No. 2004-78359).
As another example of related art, there is a wireless modem provided with both a wired external interface and a wireless external interface (Patent Document 2: Japanese Patent Laid-Open No. 2003-8684).
Furthermore, as yet another example of related art, there is a facsimile device provided with functionality for printing data from a wireless terminal (Patent Document 3: Japanese Patent Laid-Open No. 2000-232681).
However, the following problems can be considered with regards to multiple control stations.
First, it is necessary for a user to perform a switching operation or the like on the multiple control station when switching between WUSB adapter operations and wireless-direct-printing operations. When performing direct prints using a wired USB system, the user does not need to perform any particular operations with regard to the printer. Particularly, when compared to the wired USB, where the printer switches into an operational mode simply by connecting the digital still camera via a cable. On the other hand, since the multiple control station using the wireless USB needs to expressly switch an operation by the switching operation or the like, the above system lacks convenience.
Second, a situation where the adapter functionality is stopped while wireless direct printing is being executed can also be considered. Such a case presents a problem in that other WUSB devices cannot connect to the personal computer during the period in which the adapter functionality is stopped.
With regards to the related art, the technique disclosed in Patent Document 1 selects a plurality of wireless devices and connects those devices to a single USB host, and thus cannot be applied to a multiple control station that has a plurality of USB hosts.
Meanwhile, Patent Document 2 discloses a configuration in which the operational mode of a wireless modem is switched depending on the state of connections with a wired interface. For this reason, it is necessary for a user to perform operations for connecting/disconnecting devices to/from the wired interface in order to switch the operational mode, resulting in a system that lacks convenience.
Finally, according to the technique disclosed in Patent Document 3, printing and external connections are limited to a single wireless terminal only, and thus it is impossible to simultaneously provide a plurality of functions with a plurality of wireless terminals present.